For the 10/100/1000BASE-T adapter, the nxge driver and hardware support auto-negotiation, a
protocol specified by the 1000 Base-T standard. Auto-negotiation allows each device to advertise
its capabilities and discover those of its peer (link partner). The highest common
denominator supported by both link partners is automatically selected, yielding the greatest
available throughput while requiring no manual configuration. The nxge driver also allows
you to configure the advertised capabilities to less than the maximum (where the
full speed of the interface is not required) or to force a
specific mode of operation, irrespective of the link partner's advertised capabilities.

APPLICATION PROGRAMMING INTERFACE

The cloning character-special device, /dev/nxge, is used to access all Sun Neptune
NIU devices installed within the system.

The nxge driver is managed by the dladm(1M) command line utility, which
allows VLANs to be defined on top of nxge instances and for
nxge instances to be aggregated. See dladm(1M) for more details.

You must send an explicit DL_ATTACH_REQ message to associate the opened stream
with a particular device (PPA). The PPA ID is interpreted as an
unsigned integer data type and indicates the corresponding device instance (unit) number.
The driver returns an error (DL_ERROR_ACK) if the PPA field value does not
correspond to a valid device instance number for the system. The device
is initialized on first attach and de-initialized (stopped) at last detach.

The values returned by the driver in the DL_INFO_ACK primitive in response
to a DL_INFO_REQ are:

Maximum SDU is 1500 (ETHERMTU - defined in <sys/ethernet.h>).

Minimum SDU is 0.

DLSAP address length is 8.

MAC type is DL_ETHER.

SAP length value is -2, meaning the physical address component is followed immediately by a 2-byte SAP component within the DLSAP address.

Due to the nature of link address definition for IPoIB, the DL_SET_PHYS_ADDR_REQ DLPI primitive is not supported.

In the transmit case for streams that have been put in raw mode via the DLIOCRAW ioctl, the dlpi application must prepend the 20 byte IPoIB destination address to the data it wants to transmit over-the-wire. In the receive case, applications receive the IP/ARP datagram along with the IETF defined 4 byte header.

Once in the DL_ATTACHED state, you must send a DL_BIND_REQ to associate
a particular Service Access Point (SAP) with the stream.

CONFIGURATION

For the 10/100/1000BASE-T adapter, the nxge driver performs auto-negotiation to select the
link speed and mode. Link speed and mode may be 10000 Mbps
full-duplex (10 Gigabit adapter), 1000 Mbps full-duplex, 100 Mbps full-duplex, or 10
Mbps full-duplex, depending on the hardware adapter type. See the IEEE802.3 standard
for more information.

The auto-negotiation protocol automatically selects the 1000 Mbps, 100 Mbps, or 10
Mbps operation modes (full-duplex only) as the highest common denominator supported by
both link partners. Because the nxge device supports all modes, the effect
is to select the highest throughput mode supported by the other device.

You can also set the capabilities advertised by the nxge device using
ndd(1M). The driver supports a number of parameters whose names begin with adv_
(see below). Each of these parameters contains a boolean value that determines
if the device advertises that mode of operation. The adv_pause_cap parameter indicates
if full duplex pause is advertised to link partner. The adv_asym_pause_cap parameter
indicates if asymmetric pause is advertised to the link partner. The adv_autoneg_cap parameter
controls whether autonegotiation is performed. If adv_autoneg_cap is set to 0, the
driver forces the mode of operation selected by the first non-zero parameter
in priority order as shown below:

All capabilities default to enabled. Note that changing any capability parameter causes
the link to go down while the link partners renegotiate the link
speed/duplex using the newly changed capabilities.